package com.xcong.excoin.modules.gateApi;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import java.io.File;
import java.io.IOException;
import java.math.BigDecimal;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Gate 配置持久化服务 — 按 apiKey 分文件存储。
 * 文件路径: config/gate-config-{md5(apiKey)}.json
 */
@Slf4j
@Service
public class GateConfigPersistenceService {

    private static final String CONFIG_DIR = "config";
    private static final String CONFIG_PREFIX = "gate-config-";
    private static final String JSON_SUFFIX = ".json";

    private final ObjectMapper mapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);

    @PostConstruct
    public void ensureConfigDir() {
        File dir = new File(CONFIG_DIR);
        if (!dir.exists()) {
            dir.mkdirs();
        }
    }

    /**
     * 确保指定 apiKey 的配置文件存在，不存在则用默认值创建。
     */
    public GateConfigDTO ensureExists(String apiKey, GateConfigDTO defaults) {
        GateConfigDTO existing = load(apiKey);
        if (existing != null) {
            return existing;
        }
        save(apiKey, defaults);
        log.info("[GateConfig] 为 apiKey={} 创建默认配置文件", maskKey(apiKey));
        return defaults;
    }

    /**
     * 保存配置。
     */
    public void save(String apiKey, GateConfigDTO dto) {
        try {
            mapper.writeValue(configFile(apiKey), dto);
            log.info("[GateConfig] 配置已保存, apiKey={}", maskKey(apiKey));
        } catch (IOException e) {
            log.error("[GateConfig] 保存配置失败, apiKey={}", maskKey(apiKey), e);
            throw new RuntimeException("保存配置失败", e);
        }
    }

    /**
     * 加载配置，文件不存在返回 null。
     */
    public GateConfigDTO load(String apiKey) {
        File file = configFile(apiKey);
        if (!file.exists()) {
            return null;
        }
        try {
            return mapper.readValue(file, GateConfigDTO.class);
        } catch (IOException e) {
            log.error("[GateConfig] 读取配置失败, apiKey={}", maskKey(apiKey), e);
            return null;
        }
    }

    /**
     * 从 DTO 构建 GateConfig（补齐 apiSecret）。
     */
    public GateConfig buildFromDTO(GateConfigDTO dto, String apiKey) {
        return GateConfig.builder()
                .apiKey(apiKey)
                .apiSecret(GateWebSocketClientManager.DEFAULT_API_SECRET)
                // 不可调参数 — 参考 GateWebSocketClientManager 顶部常量
                .contract(GateWebSocketClientManager.DEFAULT_CONTRACT)
                .leverage(GateWebSocketClientManager.DEFAULT_LEVERAGE)
                .marginMode(GateWebSocketClientManager.DEFAULT_MARGIN_MODE)
                .positionMode(GateWebSocketClientManager.DEFAULT_POSITION_MODE)
                .restartGridSpan(GateWebSocketClientManager.DEFAULT_RESTART_GRID_SPAN)
                .priceScale(GateWebSocketClientManager.DEFAULT_PRICE_SCALE)
                .contractMultiplier(new BigDecimal(GateWebSocketClientManager.DEFAULT_CONTRACT_MULTIPLIER))
                .unrealizedPnlPriceMode(GateConfig.PnLPriceMode.valueOf(GateWebSocketClientManager.DEFAULT_PNL_MODE))
                .isProduction(true)
                .reopenMaxRetries(GateWebSocketClientManager.DEFAULT_REOPEN_MAX_RETRIES)
                // 可调参数 — 从 DTO 读取
                .gridRate(nvl(dto.getGridRate(), new BigDecimal("0.005")))
                .expectedProfit(nvl(dto.getExpectedProfit(), new BigDecimal("0.15")))
                .maxLoss(nvl(dto.getMaxLoss(), new BigDecimal("1.5")))
                .baseQuantity(nvl(dto.getBaseQuantity(), "2"))
                .quantity(nvl(dto.getQuantity(), "2"))
                .maxPositionSize(dto.getMaxPositionSize())
                .stopLossCount(dto.getStopLossCount())
                .build();
    }

    private File configFile(String apiKey) {
        return new File(CONFIG_DIR, CONFIG_PREFIX + md5(apiKey) + JSON_SUFFIX);
    }

    private static String md5(String input) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] digest = md.digest(input.getBytes(StandardCharsets.UTF_8));
            StringBuilder sb = new StringBuilder();
            for (byte b : digest) {
                sb.append(String.format("%02x", b));
            }
            return sb.toString();
        } catch (NoSuchAlgorithmException e) {
            return Integer.toHexString(input.hashCode());
        }
    }

    private static String maskKey(String key) {
        if (key == null || key.length() <= 8) return "***";
        return key.substring(0, 4) + "****" + key.substring(key.length() - 4);
    }

    private static <T> T nvl(T value, T fallback) {
        return value != null ? value : fallback;
    }
}